The present exemplary embodiment relates to a system for determining if a document page includes color, highlight color, or is achromatic or monochrome (e.g., black-and-white). In particular, the exemplary embodiment detects different color formats and splits the responsibility for their imaging accordingly to allow for efficient imaging.
Photocopiers, fax machines, scanners, electronic displays and printers have become an indispensable part of most offices, and are becoming increasingly popular for personal use as well. Color printers, including laser printers, can provide high quality text and graphic images on various document substrates, including paper and transparencies. Moreover, recently digital document processing systems, which employ printing, faxing, scanning and photocopying capabilities, have become popular.
However, existing systems have a relatively high per-page operating cost when printing color. In practice, a user may wish to print a document that has mostly black-and-white pages, and only a few color pages. For example, in a document such as a report or business plan, color pages may be used for the cover page, the first page of the different sections in the report, and for various graphs which are interspersed among a large number of black-and-white text pages. Accordingly, it is inefficient to print such a document on a color printer or photocopier when most of the pages in the document are black-and-white.
In contrast, conventional black-and-white printer or photocopiers can produce a large number of photocopies very economically. However, of course, such printers or photocopiers cannot provide color documents.
If a user desires to print several sets of a document, where the document includes both black-and-white and color pages, the user may print out one complete document, remove the black-and-white pages, and photocopy these pages to provide the necessary number of sets of black-and-white pages. Additionally, the user can print out a corresponding number of sets of the color pages, and manually collate the color pages with the black-and-white pages to form the final sets of documents. However, this procedure is time consuming, tedious and error-prone.
The prior art does include methods for splitting print jobs. A patent by Glass for a “Method and Apparatus for Split Printing of Color And Monochrome Documents,” U.S. Pat. No. 6,041,200 dated Mar. 21, 2000 splits print jobs according to chromaticity but does not concern the way page chromaticity will be determined. Also, a patent by Rumph for “Performance Optimization of Monochrome Pages and Color Printing System,” U.S. Pat. No. 6,302,522 dated Oct. 16, 2001 is a hardwired chromaticity splitting device within a printer, for splitting jobs between two different rendering paths within the printer.
Job splitting applications currently available for sale (e.g., EFI's Split or the Xerox DocuSP Color Splitter) determine whether an object is color either by rasterizing the submission and searching the resulting image for colored pixels or by searching the page description language submission for color commands. Such methods are slow, error prone, or both.
More particularly, the EFI product performs color splitting by rasterizing an input Portable Document Format (PDF) file and then pixel searches the resulting raster images. If a color pixel is found, the page is adjudged to be a color page. While potentially accurate, clearly both the rasterization and pixel search of every page's image is time consuming.
Further, at a high level, the Xerox DocuSP color splitter solution works as follows: Via Adobe Acrobat, an input PDF is converted to a PostScript file, the PostScript file is scanned for embedded Document Structuring Convention (DSC) page boundary indicators, and, to determine chromatic content, each PostScript page is searched for certain color space operators. Job tickets for both the color and black-and-white printers are generated. The color printer job ticket is used to print the identified color pages, which are then transferred to a black-and-white printer interposer. As the black-and-white engine prints the document, the black-and-white job ticket integrates the already printed direct insert color sheets with the newly printed black-and-white pages.
Further, traditional color splitting software attempts to determine whether pages require color printing capability and then attempts to intelligently segregate the color pages from the black and white pages into separate print jobs. Current color splitters only distinguish between two page types: black-and-white and contone. None recognizes highlight color pages or the specific type of highlight color (HLC).
Accordingly, it would be desirable to provide a system which detects different chromatic formats within documents and directs their printing to the most efficient printer system.